The present invention relates to a wafer cleaning apparatus and, more particularly, to a vertical batch type wafer cleaning apparatus, which can effectively increase wafer cleaning efficiency.
In the fabrication process of large-scale integrated circuits, wafer cleaning technique and cleanliness are important factors affecting yield and device quality. The object of wafer cleaning is to remove contaminants from surfaces of wafers and to remove particles and organic and inorganic impurities. Therefore, before silicon wafers enter a high. temperature oven for performing a thermal process such as diffusion or oxidation, and before or after chemical vapor deposition is performed, wafers must undergo a cleaning process to let fabricated semiconductor electronic devices conform to designed electrical characteristics.
In the prior art, a plurality of wafers are placed on a boat and dipped into a cleaning tank along with the boat so that the wafers can be cleaned using flow of injected chemical cleaning solution. However, in this cleaning method, flow of cleaning solution will be restricted between wafers so that cleaning solution and surfaces of the wafers cannot effectively interact, letting wafer cleaning effect be bad. In the prior art, a rocking or shaking means is exploited to enhance flow of cleaning solution, but the wafer cleaning effect is still not good enough. Moreover, breakage of wafers may occur because of too large rocking or shaking force. In consideration of the above problems, the present invention aims to propose a wafer cleaning apparatus, which can enhance wafer cleaning efficiency.
The primary object of the present invention is to provide a vertical batch type wafer cleaning apparatus, which can effectively increase velocity of cleaning solution flowing by surfaces of wafers to enhance wafer cleaning efficiency.
Another object of the present invention is to propose a vertical batch type wafer cleaning apparatus to let there be flow of cleaning solution between every two wafers so that each wafer can be cleaned by the cleaning solution. Still another object of the present invention is to propose a vertical batch type wafer cleaning apparatus, in which cleaning solution can be used in recirculating way, thereby reducing the cost.
According to the present invention, a wafer bearing apparatus and a flow distributor are provided in a cleaning tank. The wafer bearing apparatus is formed by arranging a plurality of wafer shelves up and down between three parallel upstanding racks. Three deflections are uniformly formed at the edge of each of the wafer shelves. The three racks have two cover bodies at two ends thereof to connect two rotators, respectively. The flow distributor is connected to a cleaning solution supply tank via an output pipe so that cleaning solution can be distributed and transferred to between the wafer shelves. Two filter pipes are further provided between the cleaning tank and the cleaning solution supply tank.